feat: adding support for systemjs remotes (#2676)

Co-authored-by: Zack Jackson <[email protected]>

Author: MadaraUchiha-314

.changeset/big-cheetahs-warn.md

@@ -0,0 +1,5 @@
+---
+'@module-federation/runtime': minor
+---
+
+adding support for loading systemjs based remotes

packages/runtime/src/utils/load.ts

@@ -33,6 +33,30 @@ export async function loadEsmEntry({
   });
 }
 
+export async function loadSystemJsEntry({
+  entry,
+  remoteEntryExports,
+}: {
+  entry: string;
+  remoteEntryExports: RemoteEntryExports | undefined;
+}): Promise<RemoteEntryExports> {
+  return new Promise<RemoteEntryExports>((resolve, reject) => {
+    try {
+      if (!remoteEntryExports) {
+        // eslint-disable-next-line no-eval
+        new Function(
+          'callbacks',
+          `System.import("${entry}").then(callbacks[0]).catch(callbacks[1])`,
+        )([resolve, reject]);
+      } else {
+        resolve(remoteEntryExports);
+      }
+    } catch (e) {
+      reject(e);
+    }
+  });
+}
+
 export async function loadEntryScript({
   name,
   globalName,
@@ -137,6 +161,11 @@ export async function getRemoteEntry({
         entry,
         remoteEntryExports,
       });
+    } else if (type === 'system') {
+      globalLoading[uniqueKey] = loadSystemJsEntry({
+        entry,
+        remoteEntryExports,
+      });
     } else {
       globalLoading[uniqueKey] = loadEntryScript({
         name,